It is known to use conventional unitary frame utility type tractors in conjunction with debris pick-up heads in order to produce utility type surface cleaning vehicles, such as a street sweeping vehicle, or the like. The many advantages of such utility type surface cleaning vehicles are well known.
Conventional unitary frame tractors have large rear tires inherent to their design and often necessary to achieve desired ground clearance. This creates an issue for maintaining a proper relationship between the gutter broom's deposited swept path and the pickup head. To achieve this, the pickup head must extend further ahead to open up in front of the rear tractor tires. Increasing the pickup head surface area to achieve this is not desirable as it would allow for a decrease in negative pressure. Instead, the duct that connects the pick-up head to the debris hopper would need to be extended in length to cover the larger distance.
Additionally, conventional straight frame tractors can turn within a tighter radius than any conventional truck unit, thus creating a further challenge for ensuring proper relationship is maintained between the pickup head and gutter broom deposited path of material at all times. Often, the front of the unit turns almost sideways causing the pick-up head to miss the debris path laid out by the gutter broom. To avoid this, the front of the pick-up head must be positioned as close as possible to the gutter brooms.
Another issue arising with newer, more compact, unitary frame tractors is the fact that there is virtually no room to run a suction duct over the axle between the inside of the rear tire and tractor frame. This requires the suction duct to come under the axle in the rear further increasing the distance the duct needs to travel from the pickup head to the debris hopper.
There are a couple of significant problems with the increased length of the suction duct. Firstly, when the suction duct requires curves to extend over the axle and enter the hopper where debris can readily clog the duct. This is highly undesirable due to the amount of work involved to remove the clogged debris, and also due to the “down time” that is experienced. Mud and other wet material have a tendency to adhere to the walls of the duct causing further clogging.
Secondly, the increased length of the suction duct causes a decrease in suction power as the material has to travel further to reach the debris hopper. This allows for a drop off in air speed, which can cause material to settle, further contributing to the clogging issue. More suction power is required to deal with the longer distance as well as the resistance created against the outer walls of the duct. It is highly desirable for a suction duct to be in direct in-line connection with the debris hopper for maximum suction power.
It is an object of the present invention to provide a utility type surface cleaning vehicles that use conventional unitary frame utility type tractors for motive power, wherein the pick-up is positioned so as to ensure the pick-up head digests path of debris laid out by gutter broom in tightest turn.
It is another object of the present invention to provide a utility type surface cleaning vehicles that use conventional unitary frame utility type tractors for motive power, wherein debris does not readily clog the duct that connects the pick-up head to the debris hopper.
It is another object of the present invention to provide a unitary type surface cleaning vehicle that uses conventional unitary frame utility type tractors for motive power, wherein suction power is not decreased with the suction duct.
It is another object of the present invention to provide a unitary type surface cleaning vehicle that uses conventional unitary frame utility type tractors for motive power, wherein the pickup head is extended to maintain proper relationship with the gutter brooms so that there is no missed debris laden swept path.
It is another object of the present invention to provide a unitary type surface cleaning vehicle that uses conventional unitary frame utility type tractors for motive power, wherein the pickup head is extended while maintaining the suction duct length from pickup head outlet to debris hopper as short as possible.
It is another object of the present invention to provide a unitary type surface cleaning vehicle that uses conventional unitary frame utility type tractors for motive power, wherein the pickup head extended longitudinally in the direction of travel without impacting its negative pressure.
It is another object of the present invention to provide a unitary type surface cleaning vehicle that uses conventional unitary frame utility type tractors for motive power, wherein the pickup head is extended allowing for the ground to assist in delivering the material back to the pickup head suction outlet.
It is another object of the present invention to provide a unitary type surface cleaning vehicle that uses conventional unitary frame utility type tractors for motive power, wherein the pick-up head is elongated along the surface allowing for material to move within the pick-up head towards the rear suction duct relative to the direction of travel of the tractor.
It is another object of the present invention to provide a unitary type surface cleaning vehicle that uses conventional unitary frame utility type tractors for motive power, wherein the pick-up head maximizes the ground clearance under the tractor when in transport mode.